Microsoft carries the highest vendor risk concentration this week across two distinct but reinforcing threat vectors: a formally documented zero-click exploit surface in agentic AI deployments including Security Copilot, and a confirmed five-month mailbox exfiltration campaign that used only Microsoft-native and legitimate cloud tooling against a financial sector executive. Neither item is patch-resolvable alone; both require architectural and telemetry responses. Organizations that have deployed Copilot features or MCP-integrated agents without embedded safety controls should treat current posture as unvalidated.